Your challenge is to make David Cameron a Liberal Democratic MP with a POD of anywhere from 1982 to 2014. Bonus points if he becomes the leader of the Lib Dems and extra bonus points if he becomes Prime Minister.
Very difficult to do, though some Tories in his cabinet were SDP members in the 1980s. I imagine that would have to be the route for him - but what is it that turns him off Thatcher ITTL?
Maybe Thatcher's social conservatism, perhaps? Anyone else have any ideas?